The invention includes embodiments that relate to an electrode composition and method of its making. The invention includes embodiments that relate to an electrode for an energy storage device.
Metal chloride batteries especially sodium-nickel chloride batteries with a molten sodium anode and a beta-alumina solid electrolyte are widely employed for energy storage applications. When the metal chloride batteries are employed in mobile applications like hybrid locomotives or plug-in electric vehicles (PHEV), the sodium nickel chloride battery should tolerate power surges (high currents) both during charging and discharging of the battery without loss in the working capacity and the cycle life of the battery. To provide better fuel economy via regenerative braking, i.e., the ratio of discharged to charged energy that decreases with the current increase, better electric efficiency is desirable.
One way of improving the performance of a battery is by the addition of small amounts of additives to the cathode compositions. Additives employed in the art include sodium salt of halogen other than chloride (sodium iodide, sodium fluoride, and sodium bromide), elemental sulfur, sodium sulfide (Na2S), iron sulfide (FeS), and combinations of the foregoing additives. However, use of these additives neither substantially help in increasing the low working capacity of the battery nor helped in minimizing cell capacity degradation, particularly for batteries employed in high current applications.
Therefore, there exists a need for an improved solution to the long-standing problem of high current cell performance by addition of additives for the electrode that significantly improve the cell working capacity and decreases the capacity degradation rate.